Floating sealing device



@ci 26, 1948.- D. FgMCGlLL 2,452,253

FLOATING SEALING DEVICE i Filed Jan. 29. 1945 2 sheets-sheet 1 DANxEL F.M u L Oct. 26, 1948. D. F. McGxLL 2,452,253

'FLOATING SEALING DEVICE Filed Jan. 29, 1945 2 sheets-sheet 2 W//l//l/l/Patented Oct. 26, 1948 NITED STATES vPAiji-s.;N"r OFFICE i 2,452,253 i.my

FLoA'rINo sEALING DEVICE- l nanimmsiu, Portlanapyegy y imputationJanuaryze, 1945, serial No. 575,001 f This invention relates to sealing.devices for use between relatively rotating .parts in apparatus such asrotary'. and centrifugal pumps, steam turbines, hydraulic powertransmission mechanisms and the like, for sealing a high pressureareafrom a low pressure area.

The invention is illustrated and described herein as applied to rotary'type pumps comprising a driven element rotatably mounted in acylindrical casing and equipped with a plurality ofA radially extendingblades forming a plurality of uid chambers between the inlet anddischarge sides of the pump. Each end face of the rotor is recessed toprovide an annular shoulder extending axially from the end face of therotor, and disposed between eachend face of the rotor and the end wallof the casing is a sealing ring, a portion of the ring being receivedinthe recess in the end face of the rotor and having 'sliding sealingengagement with the annular shoulder. The sealing rings are fastenedtogether' as by bolts or rivets extending through the 4rotor, thesealing unit comprising the sealing rings being of xed over-all axiallength and having running sealing engagement with the end walls ofthehousing. Theopenings through the rotorV for thebolts or rivets are ofsufficientsize to permit free axial movement of the rotor in response tothe end thrust created by adjustment of the shaft bearings or byoperation of the driving means. in rotary pumps embodying prior artcon-- structions endwise movement of the shaft induced by operation ofthe driving means vmay cause the rotor to engage with one or the'otherof the end walls of the casing and have bearing contact therewith. rWhenthis Occurs hydraulic pressure is exerted on the opposite-side 4of therotor, creating a friction load betweenthe rotor and the easing indirect proportion tothe pressure rdeveloped by the pump, and resultingin wear and subsequent leakage or the fluidbetween the rotor and thecasing head.

It is, therefore, an object o' ther-instant invention to provide asealing unit disposed between a rotor and a stator in apparatus suchfasrotary type pumps and the like in which the rotor may be suiiicientlyshorter than the axial -length of the rotor chamber as to avoid wearingcontact 'between the rotor and the stator, thereby greatly increasingthe emci'ency of the unit and materially lessening. its usefullife.

It is a further object of the invention tof'pro'- vide in combinationwith a rotor and stator a .sealing uniteomprising ya sealing fri-rig.'disposed .between theistator andfeach'vend 4face-of tnerotor,

1o claims. (C1. 10s- 202) each said sealing v, ring having runningsealing engagement with 'the stator and sliding sealing engagement withthe rotor for sealing a high pressure area from a low'pres'sure area.

It is a further object of the invention to provide in an apparatuscomprising a rotor and a stator, and in which the axial length of therotor is suicientlyvless than the axial length of the stator as topreclude Contact between the rotor and the end walls of the stator, asealing unit comprising a sealing :ring disposed between each Lend faceof the rotor and the stator for sealing a high pressure area from a lowpressure area.

It is a further object of the invention to provide in any apparatuscomprising a rotor and a stator, and in which the axial length of therotor is suieiently less than the axial length of the stator as topreclude contact between the rotor and the end walls yof the stator, asealing unit comprising a sealing ring disposed between each endface ofthe rotor and the stator, each said sealing ring having running sealingengagement with the stator' `and slidingl sealing engagement `with therotor and permitting endwise movement of the rotorin'. response to endthrustinduced by adjustment of the shaft bearings or by operation of thedriving means.

It is a further object .of the invention to `provide a novel sealingdevice .for rotaryy type pumps and the like for greatly reducing thefriction and hydraulic losses usually occurring in this type ofequipment.

A further object/tof the l'invention is to provide va novel sealing.device adapted for use between the rotor yand .the housing of rotarytype pumps and the like which enables the use rof a rotor of suchzaxialdimensions a-s to be mounted :entirely `out of contact with :the endwalls of theA pump housing. 'I-he desired obgiects andadvantages of theinvention are obtained `through the `novel larrangement and uniqueconstruction and improved combination of the various parts hereinafterdescribed and as illustrated on the accompanying drawings, it beingunderstood that various changes in form, proportion, size and details ofconstruction within the scope' of .the v,claims may be resorted to.without `departing from the spirit or sacrificing any .of the:advantages of the in vention.

`In the drawings: Figure 1 is a sectional elevaltion, inaplaneparallel'with the axis of the rotor,

of :a rotary pumpernploying a sealing device compri-sing. an embodiment:of `tlfle invention; Figure 2 is a sectional elevation of the rotarypump shown in Figure 1, taken in a plane perpendicular to the axis ofthe rotor; Figure 3 is a fragmentary perspective view of one of thesealing rings employed in the construction illustrated in Figures 1 and2; Figure 4 is a fragmentary sectional view taken on the line 4 4 ofFigure 2; Figure 5 is a fragmentary sectional elevation of a rotary pumpillustratinga modicatipn of; the lsealing Ydevice shown in;A Figu'rexll@Figure 6 lis; a; fragmentary perspectiveview of oneof the sealingringsem-v ployed in the construction illustrated in Figure ment with theouter wall I9 of the recess.

4 of their connection with the rotor I'3 through the connecting bolts orpins 22.

Each sealing ring 2I is of such thickness that it extends only partlyinto the annular recess I8 in the end face of the rotor to allow for endmovement of the rotor and still have sealing engage- The recess is ofsuch depth that the rotor I3 may have axial movement in response to endthrust with- `out lthe inner recessed wall 25 of the rotor I3 contactingthe' inner face of the sealing ring. The

sealing rings 2 I-2I form with the rotor I3 a seal 5; Figure 7 is afragmentary sectional elevation" of a rotary pump illustratingafurtherlmodicaf tion of a sealing device embodying the invention;AFigure 8 is a fragmentary perspective view :of 'onev of the sealingrings employedfinthaconstruction shown in Figure '7; Figure 9 is afragmentary sectional View of a centrifugal pump showingianf l applied`to y1a--rotaryv pump comprising-a casing 9 ofgenerally cylindrical"fouilland:closedy at its opposite ends by casing heads 7'I0.secured Atothe casing Bas by bolts I I or similar fastening means. The casing 9ldefines arotorrcharnber I2 within whichis mounted :acrotor I3 having aplurality of equally spaced radially'extending slots I4'within. whichare mountedrotonblades I5- having close 'runningtolerance;alongxtheirside edges with the. inner faceszof the casingheads Ill and engaging thecylindrically formed inner Ywall surface I6 of the casing i whichvdefines the; rotor chamber.v Y'libe-casing headsflll mat7 or may not bevprovided with? suitably packed lglands as depsired.` The casinguQ isprovided `with oppositely disposed inleltdandY discharge4port/5respectively,

1n' the constructies illustrated in Figure 1 each end face I1 of'therotor is provided with, an

annular recess I8, at lea-sttlie outer side wall IS of the' recess beingcarefully' machined so as to *i provide a close sliding flit withlasealing ring 2| n mounted between eaehend face of the rotor I3 and thecasing head'l.' 'It will be noted that the axial length of the rotor I3is less than' the axial length of the rotor' chamber I2; so that'each'end face Il of the vrotor'I3'is spaced from' the inner lface Iofthe casing he'adfl'll;z Disposed' between each end'face I'I of the rotorI 3`and the adjacent casing head IIlis a sealing ring 2|,` a portion ofthe ring being -received in lthe annular recess `I3 in the end face ofthe rotor. The sealing' rings lI--2I are fastened'togetherf'as byboltsor Apins 22, provided with: shoulders 23ia`djacent each end the openingtherefor being Yfof suicient lsize to ypermit free axial movement of therotory I3 in response to the end thrust created duringradjustment of theshaftbearings or'by operation of the l w "70 driving means. The sealingrings 2 I-2 I and bolts 22 form a rigid unit ofi'ixed overall lengthsuch Aas to provide a close runningtolerance `with the end wallsy 2A of.the rotor. chamber.l l' The sealing rings 2I Vare rotatably mounted,within the rotor chamber,,rotation thereoflbeingefected `by rea-son atthe point of contact 26 between each sealing ``ringZI and the outer wallI 9 of the annular recess I8, anda seal at the point of contact 21between the'endface 28 of each sealing ring and the casing g head, forpreventing the loss of fluid from the pump.

' Insprior art constructions the end thrust induced by operation of. thedriving means may cause therotor to engage with one or the other ofjthecasing headsand have bearing contact therewith, thereby causing thehydraulic pressure developed by the pump to be exerted on theoppositeside of therotor. lThis condition creates a friction loadbetween the rotor and the casing in direct lproportion to the pressuredeveloped by the pump, and results in Wear and subsequent leakage of theliquid between the rotor and the casinglhead. In a pump embodying theinstant inventiomby reason of the fact that the rotor may be greatly'shortened-relative tothe axial length rof. the rotor chamber, the rotorI3 cannot engage the veasing heads Il), being held out of engagementtherewith by adjustment of the shaft belings 1Asillustrated in Figure 3,the sealing rings 2I are provided with radial slots 29 within which aremounted the respective end portions of the Vrotor'dblades I5, thesealing rings 2I, however, being ofhsufficient radial width a-s to havean unslottedv-:portionSI which serves to hold the several `segments ofthe sealing ring in integral relation. d -In-the constructionillustrated in Figures 1 and 2 holes 32 drilled inthe rotor i3 extendfrom the bottomof the radial slots Idto the 'pressure side of-.the rotorblades I5 for admitting fluid under pressureto the slot i4 for urgingthe blades into engagement with the ,arcuate wall I6 of the rotorchamber. ySince the slots I4 communicate with the annular recesses I8,and since the annular re eessesare of greater depth than is occupied bythe sealing ring 2 I, fluid under pressure from the chambersbetweenadjacent rotor blades would be likely to flow along the channelsformed by the annular recesses I8 from a high pressure area to a lowpressure area. To prevent such ow from occurring,1which, obviously,would impair the eili- :ciency of thepump, a plurality of radial slots33 are provided in theinner faces of the sealing `rings 2 I, one slotbeing provided between each adjacent two of the rotor blades, as shownin Figure 4.A Secured to each end face of the rotor I3 and extendinginto each one of the slots 33 is a radially disposed rib 34k so mountedon the end face of the rotor vvas to provide sealing engagement with atleast one side wall of the slot 33 in the sealing ring. Bygthis means,.the channels formed by the annular recesses I8 in the end faces oftherotor are effectivelypsealedrat a point between each adjacent two of therotor blades and the flow of fluid from. the pressure chambers ofthepump to a low pressure larea is prevented. A L Inl Figure 5 is shown arotary pump comprising ,al casing 35 and casing head 361dening a rotoramazes l "chamberv` 31' within V-whi'chis "mounted a'rotor'l 38.

In'this construction the casing head'36' is prorvidedwithan annularrecess' 39 in its `inner face,

'-'andeach end face 4I 'of' the'rotor 38 is recessed yto provideanannular shoulder 424 substantially `'inaxialv alignment; though notnecessarily so, with the annual shoulder 43 ofthe recess 39 in thecasing head 38. A'sealingring 44 is disposed between reach end face 4'!of the rotor and the casing head "36,thesealing rings44 being'disposedvon the opposite ends of pins 45 which iixedly khold the sealingjrings inspacedv apart relation so that the overall axial length of theinterconnected sealing rings "isfsuch as to provide a running sealingengage- 'ment with the recessed faces 39 of the casing ifheads. The pins45 connecting the sealing rings ''4'4extend through the rotor 38 so thatthe sealing "rings44 are caused to rotate therewith.

Each sealing ring 44 is of sufficient thickness in 1 the axial directionto extend into the recess 39 in thecasing head and to project under theannular W"shoulder 42 on the end face of the rotor for forming a sealagainst the passage of iiuid therebetween. Axial movement of the rotor,such as may 'take lplace in response to the end thrust inducedMbyoperation of the driving means or adjustment rof the shaft bearings,causes a relative movement between the sealing ring and the rotor, theannular shoulder on the end face of the rotor having vsliding engagementwith the peripheral face of 'the' sealing ring.

Asshown in Figure 6, each sealing ring 44 is -:provided vwith radiallyextending slots 46 to re- 4vceive the rotor blades therein, the bottomof each Vslot 43 being in the'plane of the innermost surface 41' of thecasing head, the unslotted portion 49 of the ring extending into therecess 39 in the casing head and forming a seal at the point of contactl*between the end face' 5i of the sealing ring and the casing head.

A slightly different structure is illustrated in 'Figure 7 in which isshown a casing 52 provided with casing heads 53 defining. a rotorchamber 54 inwhich is mounted a rotor 55. The casing headsr453arerecessed to provide annular shoulders 55, l,and the end faces ofthe rotor 55 are similarly 'recessed to-provide annular shoulders 53.The recesses 59 in the casing heads 53 are of smallerdiarneter than arethe recesses in the end faces 5l of the rotor 55 whereby the annularshoulders 58 are offset in the radial direction from the shoulders 55.The construction illustrated comprises sealing rings 6| disposed betweenthe rotor 55 and the casing heads, each sealing ring extending into 1.arecess `5'! in the end face of the rotor 55 and `having vsealingengagement with the annular .shoulder-58. A' portion-of each sealingring extendsinto the-recessES inthe casing head, the

roverall axial length ofthe sealing unit, however,

being less than the distance between the recessed faces of the casingheads so that each sealing ring isloosely fittedbetween the recessed endface of the rotor and the recessed wall ofthe casing head.

The sealing rings 5! are rabbeted to provide fshouldersoverlyingtheinner faces 53 'of the casing heads 53 outwardly of the recesses 59.The sealing rings are mounted on the reduced end portions of pins 64which hold the sealing rings in predetermined spaced apart *positionwith the shoulders 52 thereof in running engagement with "theA faces v63of the casing heads-for effecting a seal therebetween. lAs'showninligure8, each sealing ring is provided with radiallyextending slots 35,onefor-:each of the rotor blades, the bottom of eachslot'being in'theplane ofthe innermost surface 53 of the casing heads, the unslottedvportion of each'ring lying within the recess 59 in the casing headserving to hold the several segments of the sealing ring iniiitgralrelation.

In Figure 9 is illustrateda fragmentary portion of'a pumpcajsin-ghavingwalls 55de'iningl a pump `chamber lhavng mounted thereinan impeller. *The -`impel-ler` comprises shroud plates- Gil-58 having'impel'ler varies'Y 59 extending therebetween.

Adjacent its discharge end the impeller is prov"Videcl'withoutturnedannular flanges 'il extend- "ingin the direction'of the walls 550i therpump casing. lA sealing ring'ifZ is mounted between :each-shroud' plateGSand the adjacent casing wall 55, the two sealing rings 'l2-72 beingintercon- :nected 4by means ofra bolt or pin i3-extending :looselythrough the impeller and holding the sealving-rings iixedly in spacedapart predetermined rel-ation so that the overall length of the sealingunit comprising the two sealing rings is such as to `provide a runningsealing engagement with the inner faeesifll of the casing-walls. Each-ofthe sealing rings l2 is held in sealing engagement `with"theouttu-rnedannular flange il on the-impeller-so as to form therewith a seal againstthe Vpassage of ii-uid therebetween. The thickness of each sealing ring'lf2 is less thanthe distancebe- Vtweenthe'impeller shroud andtheadjacent wall of -thefpump casing, theannual nianges yhaving slidingengagement with the sealing rings in the eventof axial movement `of theimpeller.

-InfFigu-re 10 lis illustrated a sealing unit-comprising a pair ofsealing rin-gs 'l5-'i5 rheld iixedly in spaced apart-predeterminedrelation by means ofbolts or pins 15, only one of whichis shown. Thesealing rings aref-mounted on reduced end ,In each'of the modificationsdescribed herein,

:the sealing rings are so. interconnected as to have xa fixed' overall.length providing for close running engagementwith thepump housing foreffecting .a seal therebetween. In each modification, also, .the sealbetween veach sealing ring andthe rotor .draulically balanced andnotsubject toend thrust.

Thus the sealing .rings may be. said to float between the casing'heads,the fluid from the pump chambers tending ,to lubricate the seal so thatvery little friction is developed between the seal- .ing rings and theeasingzheads.

Having now described my. invention and in what vmanner .the same may beused, what I claim as new. and desire to protect by Letters Patent is:

l. A sealing device comprisingin combination a stator, a rotor, and asealing unit, said sealing unit -comprisinga pair of sealing ringsdisposed between.adjacentportions of the stator and rotor .on .oppositeends of said rotor, and'means interconnecting said sealing rings vformaintaining them in sealing engagement with said stator, said `.anstattSealing rings being caused to rotate with said rotor and having slidingengagement with said rotor and forming therewith a seal whereby saidrotor may have axial movement relative to said stator and said sealingunit.

t 2. A sealing device comprising in combination a stator, a rotor and asealing unit, said sealing unit comprising sealing rings disposedbetween each end face of said rotor and the stator, a plurality ofopenings extending axially through said rotor, a plurality of pinsdisposed in said openings and interconnecting said sealing rings .forholding said sealing rings in sealing engagement with said stator, saidpins slidably engaging said rotor for permitting axial movement of therotor relative t0 said sealing unit, said sealing rings slidablyengaging said rotor and forming therewith a seal while permitting freerotation of said rotor within said stator.

3. A sealing device comprising in combination a stator, a rotor and asealing unit, said sealing unit comprising a pair of sealing ringsmounted one between each side of said rotor and the stator, a pluralityof pins interconnecting said sealing rings, said pins having reduced endportions forml ing shoulders against which said sealing rings are seatedfor holding said sealing rings in predetermined spaced apart relationand in close running engagement with said stator but separated from saidrotor, said pins being carried by said rotor whereby said sealing ringsare caused to rotate therewith, said sealing rings forming with saidrotor and said stator a seal, said rotor slidably engaging each of saidsealing rings whereby said rotor may have axial movement relative to i'said stator and said sealing unit.

4. A sealing device comprising in combination a stator and a rotor and asealing unit, a recess in each end face of the rotor forming an annularshoulder, said sealing unit comprising a Sealing lring disposed betweeneach end face of lsaid rotor and said stator and having slidingengagement with said shoulder, a plurality of pins extending vthroughsaid rotor and engaging said rings for holding said rings in runningengagement with said stator, the inner face of each' said ring beingspaced from said rotor for permitting axial movement of said rotor, saidsealing rings forming with said stator and with said annular shoulder aseal.

5. A sealing device comprising in combination a stator, a rotor and asealing unit, said sealing unit comprising a sealing ring disposedbetween each end face of the rotor and the stator, a plurality ofopenings extending axially through said rotor, a plurality of pinsdisposed in said openings r and engaging said sealing rings for holdingsaid sealing rings in predetermined spaced relation and having reducedend portions forming shoulders against which said sealing rings areseated so as to be held in close running engagement with the saidstator, said pins slidably engaging said openings for permitting axialmovement of said rotor, and means on said rotor slidablyengaging saidsealing rings and forming therewith a seal, each said sealing .ringthereby forming between said rotor and said stator a seal.`

6. A sealing device comprising in combination a stator, a rotor and asealing unit, said rotor having an annular recess in each end facethereof and radial ribs extending transversely of said annular recess,said sealing unit comprising a sealing ring disposed between each endface of the rotor and the stator and being disposed partly within saidrecess, radially disposed slots in said sealing rings, said ribsengaging in said slots for preventing flow of fluid in said annularrecess.

'7. A sealing device comprising a stator, a rotor, and sealing rings,said rotor being provided with an annular recess forming an annularshoulder on each end thereof and having an axial length less than thatof the `rotor chamber so that each end face of the rotor is spaced fromthe corresponding inner face of said stator, said sealing rings being sodisposed that they are in part received by the said annular recesses andhave sliding engagement with the shoulders thereof, a plurality of pinsextending axially through the rotor and having sliding engagementtherewith, said pins having reduced end portions forming shouldersagainst which said sealing rings are seated so as to be held out ofengagement with the end face of the rotor but in close runningengagement with the said stator, thereby forming between the rotor andstator a seal, while at the same -time permitting endwise movement ofthe said rotor without Contact of the rotor with the end walls of thesaid stator. Y

8. A sealing device comprising a stator, a rotor and a sealing unit, anannular shoulder extending axially from each end face of said rotor,said seaiing unit comprising a sealing ring being disposed between eachend face of the rotor and the stator, means interconnecting said sealingrings for holding them in a predetermined spaced apart relationship suchthat the overall axial length of theV interconnected sealing rings issuiiicient to provide a running sealing engagement with said stator,each said sealing ring being of sucient width to extend into sealingengagement with the shoulder on the rotor but of insufficient width toengage the end face of the rotor. i

9. A sealing device comprising in combination a rotor, a housing, and asealing unit, said sealing unit comprising sealing .members disposedbetween adjacent portions of the rotor and housing and forming therewitha seal, means carried by said rotor and interconnecting said sealingmembers for holding said members in running sealing engagement with saidhousing, said means causing said members to rotate with said rotor andhaving free relative movement axially in said rotor. v

l0. A sealing device comprising in combination a stator and a rotor anda sealing unit, said sealing unit comprising a -pair of sealing ringsmounted one between each side of the rotor and the stator, meansextending through said rotor for holding said sealing rings in closerunning engagement with said stator, each said sealing ring forming withsaid rotor and said stator a seal, said sealing unit and said rotorhaving free relative movement solely in the axial direction of saidrotor,l said sealing unit and said stator having only relativ rotationalmovement.

DANIEL F. MCGILL.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,716,901 Rochford June l1, 19291,996,875 McCann Apr. 9,-1935 FOREIGN PATENTS Number Country Date564,319 France v 1923

